Wednesday, May 18, 2016

It is not exactly breaking news that the Ebola virus may persist in some organs and bodily fluids (i.e. semen, breast milk, etc.) for months (seeECDC On Ebola Persistence & Rapid Risk Assessment) after victims recover. Nor is the potential for sexual transmission, or transmission via breast feeding.

Due to the possible risk of virus persistence
in breast milk, EVD survivors who are lactating are encouraged to have
their breast milk tested for Ebola virus by RT-PCR. Women who do not
know the status of their breast milk or who were tested and for whom no
Ebola virus RNA was detected should continue breastfeeding. If Ebola
virus RNA is detected, breastfeeding should be suspended and the breast
milk retested every 48 hours until two consecutive “undetected” results
are obtained

Today, however, we have a study - published in the journal Virus Evolution - that used genetic sequencing to identify the lineage of Ebola infections during the tail end of the outbreak in Sierra Leone, and which indicates sexual or breast milk transmission was likely in a handful of cases.

Given the formatting challenges we'll skip directly to the press release from Wellcome Trust, one of the sponsors of this study, which provides some background and details on their findings. Follow the link to read it in it's entirety.

Some of the final cases of Ebola in Sierra Leone were transmitted
via unconventional routes, such as semen and breastmilk, according to
the largest analysis to date of the tail-end of the epidemic.

An international team of researchers has produced a detailed picture
of the latter stages of the outbreak in Sierra Leone, using real-time
sequencing of Ebola virus genomes carried out in a temporary laboratory
in the country.

While the study did not suggest that unconventional transmission was
more common than previously thought, the authors describe several
instances including a mother who may have transmitted Ebola to her baby
via breastfeeding, and an Ebola survivor who passed on the virus
sexually a month after being released from quarantine. [More details of
cases in the notes to editors].

The research, published today in the journal Virus Evolution,
suggests that rapid sequencing of viral genomes in the midst of an
epidemic could play a vital role in bringing future outbreaks under
control, by allowing public health workers to quickly trace new cases
back to their source.

(SNIP)

Starting in mid-2015 samples from all new Sierra Leone cases were
rapidly sequenced in the facility. The data, combined with the growing
reference set, helped field workers locate the source of infection for
some of the final Ebola cases in Sierra Leone. This work revealed that
some cases were acquired through unconventional transmission chains and
supports a growing body of evidence that the Ebola virus can be found in
fluids such as semen or breast milk and may persist beyond the standard
quarantine times.